204 REPORT—1904. 
in which hydrogen chloride is electrolysed. But when a methyl-group is 
transferred there appears to be a complete separation of the radicle (e.g. as 
CH,Cl) and subsequent recondensation, giving rise not only to isomerides, 
but also to higher and lower homologues. 
6. Influence of Catalytic Agents.—Isomeric changes of this type usually 
take place only in presence of strong acids, whilst alkalies prevent rather 
than assist the change,! as is shown by the stability of the salts derived 
from labile sulphonic acids, diazohydroxides and oximes, and by the 
readiness with which good yields of compounds such as phenylchloro- 
acetamide and /3-phenylhydroxylamine are obtained by alkaline or neutral 
methods of preparation. The conversion of ammonium cyanate into urea 
may be regarded as due to the dissociation of the cyanate and recondensa- 
tion of the resulting NH; and HCNO— 
NH, CO NH, 
Shave Cnet ; was (a aged CO ; 
NH NH,/ 
whatever view be taken of this condensation it is evident that the ammonia 
is resolved into the two radicles H and NH,, and so functions as an acid 
rather than as a base ; there need therefore be no hesitation in classifying 
this change with the dissociation and association of acids which characterise 
this group of isomeric changes. 
IV. Isomeric Changes in which a single Mobile Radicle is Transferred. 
To this group belong all those cases in which a mobile hydrogen atom 
is transferred from oxygen or sulphur to carbon or nitrogen, as in the 
ketones, nitro- compounds and oximes, together with the few cases in 
which it is possible to prepare isomeric salts from these. The transference 
of an anion is less frequent but Hantzsch has described a number of cases 
in which a mobile OH or CN group is transferred in precisely the same 
way as the mobile hydrogen atom. The group of changes in which a 
mobile hydrogen atom is transferred includes the most important cases of 
dynamic isomerism and forms one of the most fully investigated, and at 
the same time one of the most fertile, branches of organic chemistry ; the 
great wealth of examples must be attributed to the neutral character of 
the hydrogen atom, which is equally ready to play an inert part in a 
hydrocarbon, or to associate itself with a powerful negative radicle in the 
mineral and organic acids. 
All the members of this group undergo isomeric change with great 
readiness. This is probably due to the fact that in every case at least one 
of the isomerides is an electrolyte, and so can take its place in an 
electrolytic circuit instead of acting merely as a depolariser. Thus, 
although it is difficult to think of pseudo-acetone as anything but an 
unsaturated alcohol, the proximity of the double bond gives it at least 
a superficial resemblance to acetic acid and probably confers upon it 
distinct electrolytic properties : 
oa oe 
CH,.C0O.CH CH..C CH,.C 
3 3 3 \cH, 3 Xo 
Acetone Pseudo-acetone Acetic acid. 
! Exceptions to this rule are found in cases in which an interchange of radicles 
depends on a double ketoenolic change or on a reversible hydrolysis, as in the case 
of a and 8 glucose. 
